1. Field of the Invention
This invention relates to a container closure having a liner and a method for its production. More specifically, it pertains to a container closure with a liner which has excellent sealing properties, openability and hygienic characteristics.
2. Description of the Prior Art
The provision of some sealing material is required in container closures such as crown caps and other types of caps in order to ensure sealing of the mouth of a container such as a bottle. A plastisol composed of vinyl chloride-type resin particles dispersed in a plasticizer has been widely used as a liner-forming material for container closures because it can be applied in a flowable condition to a closure of any shape and can be easily formed into a sealing liner by heat gellation, and it obviates the troublesome operation of producing liners by stamping and applying them one by one to closures which is required in the case of using disc-like packings as liners.
Heretofore, adipate plasticizers such as dioctyl adipate or phthalate plasticizers such as dioctyl phthalate and dibutyl phthalate have been widely used in the plastisol. The deleterious effect of these plasticizers on foods and drinks in containers remains a problem, and it is much desired to develop a plastisol which can replace the conventional one.